The ECG machine (or called EKG machine) captures the electrical signals generated by the heart through electrodes placed on the surface of the human body and converts them into a visualized waveform. The correct use of electrodes is directly related to the clarity and integrity of the recorded electrocardiogram signals. If the electrode is placed improperly or connected improperly, it may cause distortion of the electrocardiogram waveform, increased signal interference, and even miss important pathological information, thereby affecting the doctor's diagnostic judgment. Users need to select qualified electrodes and lead wires and must have qualified professionals to perform standardized operations.
For a 12-channel ECG machine, the standard 12-lead electrocardiograph is the most commonly used type in clinical practice. By placing 9 or 10 electrodes at different positions on the human body, it forms 12 ECG leads. The electrode position follows internationally recognized standards, usually using Wilson or Cabrera standards, and is divided into limb leads and chest leads.
There are various types of electrodes for electrocardiography, usually divided into reusable electrodes and disposable electrodes. Reusable electrodes include chest electrodes, also known as suction bulbs, and limb electrodes, also known as limb clamps. For adult and pediatric patients, the reusable electrodes are different on size. Disposable electrode pads are more convenient and comfortable to use, but they have a higher cost. In most cases, disposable electrode pads are not the preferred choice.
Regardless of which type of electrode the user chooses to use, the position of the electrode must be placed according to regulations.
The position of limb electrode:
Limb leads are mainly used to record electrical activity in the horizontal and vertical planes of the heart, helping to evaluate the electrical axis of the heart, ventricular hypertrophy, and other conditions.
The position of chest electrodes:
Chest leads are mainly used to record the electrical activity of the anterior, lateral, and posterior walls of the heart, and are of great significance for the diagnosis of diseases such as myocardial infarction and ventricular hypertrophy.
When placing and connecting electrodes, operators need to pay attention to:
1. Skin cleaning: Before placing the electrode, the skin should be cleaned with alcohol or specialized cleaning agents to remove oil and dirt, in order to reduce resistance and interference. Please note that some patients may be allergic to certain cleaning agents, and it is necessary to choose the appropriate cleaning agent based on the patient's condition.
2. Apply conductive paste: If necessary, apply an appropriate amount of conductive paste evenly at the corresponding position to better conduct the current signal. The use of conductive paste also needs to consider the issue of patient allergies.
3. Appropriate pressure: The electrode should be tightly attached to the skin, but excessive force should be avoided to avoid discomfort or skin damage.
4. Avoid interference sources: The electrode position should avoid areas such as bone protrusions, scars, tattoos, etc. that may affect signal quality, while also being away from objects such as metal substances and electronic devices that may cause interference.
5. Maintain stability: During the recording process, patients should maintain calm breathing and stable posture, avoiding movement or speech to reduce interference.
If you need a detailed understanding of electrodes and connection methods, you can refer to our video 'Connecting ECG Electrodes and Record ECG' in YouTube. Please visit: https://youtu.be/lGpg4uJfzB4.
The accuracy and standardization of electrocardiographic electrode positions are one of the keys to ensuring the quality and diagnostic accuracy of electrocardiograms. Medical staff should be proficient in the placement of electrode positions and strictly follow standardized procedures in practical operations to improve the accuracy and reliability of electrocardiogram examinations.